There are numerous technologies available for packaging semiconductor dies. Packages are typically chosen based on criteria such as reliability, such as Mil-Spec devices utilizing hermetically sealed packages, operating power and temperatures such as power supply and converter circuits, and cost such as basic plastic or ceramic packages for commercial applications.
Schottky devices are used extensively in power supply and converter outputs for military and space systems. These high reliability applications require the use of a hermetically sealed package to prevent moisture from contacting the die and degrading electrical performance. There is a great need for hermetic Schottky devices in small surface mount packages to reduce the size and weight of the circuit.
High power devices, such as transient voltage suppressors (TVSs), are configured to prevent damage to protected circuits by high voltage spikes. These TVSs are designed to operate at voltages up to about 500 volts for single die packages, and multi-stacked dies may be employed for higher voltages, although these devices are much more complex and expensive. One of the basic limitations of single high voltage die TVSs is that the dies will arc and become inoperative if they are subjected to excessive voltages.
High voltage rectifiers above 500 V are very common in the micro-electronic industry. Electrical arcing internally to the micro-electronic package, either across the die itself or from package electrode-to-electrode, is always a concern. A common solution is to add a dielectric polymer coating over the high voltage die to prevent arcing. For high reliability devices, such as Mil-Spec devices, hermetic packages containing polymer dielectric coatings are problematic due to the polymer's temperature limitations and high thermal expansion causing potential reliability issues after temperature cycling.
There is desired a semiconductor device and package that is operable well over 500 volts and that is not prone to arcing, including devices that are operable over 1000 volts. Such a device and package should be suitable for a single die device.